It is known to provide a motor-driven hydraulic fluid pump which can be made to communicate with the fluid supply and, via pump branch lines beginning at a pump line, with a chamber of at least one lifting cylinder and of at least one closing cylinder, which rotates the lifting platform and closing wall combination, respectively, via associated control valves. A pressure transformer and piston cylinder unit is connected across the pump branch lines.
In previously known control devices of this type, a problem has arisen in practice that, if the load is not positioned on the combination lifting platform and closing wall in accordance with regulations, or directions of use, for example being off-center or an overload, tilting torques may arise which translate into increased tensile and compressive forces in the lifting arms and in the closing cylinders of the combination platform and closing wall. For example, the allowable forces may be exceeded by up to a factor of 5, which can damage or destroy the lifting arms and/or the closing cylinders.